Hear Exchanger - Westerbeke 3.5 SBCG Operator's Manual

SAFETY SHUTDOWN SENSORS AND SWITCHES
SAFETY SHUTDOWN SWITCH/SENSORS
The engine is protected by four automatic shutdown circuits.
Should a shutdown occur, do not attempt to restart without
finding and correcting the cause.
Refer to the heading
Engine starts, runs and then shuts down in the ENGINE
TROUBLESHOOTING section of this manual.
The following is a description of these automatic shutdown
circuits:
High Exhaust Temperature Switch
An exhaust temperature switch is located on the water
injected exhaust elbow. Normally closed contacts, this switch
will open and the ECU will interpret this as a high exhaust
temperature issue and de-energize the K2 and K3 relays,
stopping the generator.
liiGH EXHAUST______, .
TEMPERATURE
SWITCH
Main AC Circuit Breaker
. EXHAUST ELBOW
The main circuit breaker at the control panel will
automatically disconnect the AC power if there is an
overload. This circuit breaker must be manually switched off
when servicing the engine/generator.
Engine DC Circuit Breaker
'20A CIRCUIT
iBREAKER
·MAIN AC CIRCUIT
BREAKER
The generator's engine DC circuit is protected by a rocker
type DC 20 amp breaker mounted on the control box.
This
also serves as an Emergency Stop Switch. Excessive DC
current draw or DC electrical overload anywhere in the
instrument panel wiring or engine wiring will cause the
breaker to trip to the OFF position. In this event, the DC
power to the ECU will be interrupted, stopping the generator.
No panel LED will illuminate. Check and repair the source
of the problem. After repairing the fault, reset the breaker and
restart the generator. The DC breaker must be cycled OFF
then ON to clear any ECU shutdown from the ECU after the
fault situation has been repaired.
11
Fuses
A FL-15A fuse located on the control panel protects the
electrical wiring. If an amperage overload occurs, the fuse
will blow and shut down the engine.
A 20A ATM fuse protects the battery charging circuit. If this
fuse fails, the engine will continue to run but the battery will
not
be cha<ging.
~
ATM 20A.FUSE
Oil Pressure Sensor
An oil pressure sensor is located off the engines oil gallery.
Oil pressure on the sensor affects the DC voltage through the
sensor to the ECU. Should the voltage reach a preset value,
the ECU will interpret this as a low oil pressure issue and
open the K2 run relay, stopping the generator. The oil
pressure LED on the panel will illuminate.
Oil Pressure Switch
The oil pressure switch sensors the engine's oil pressure. If
the oil pressure falls below 5 PSI, the switch will shut off the
fuel pump and the engine will shut down. Thw switch will
reset itself when the oil pressure is restored.
Water Temperature Sensor
A water temperature sensor is located at the thermostat _
housing. This resistance of the sensor changes as a function
of temperature. The ECU measures this resistance and
converts it to the corresponding engine coolant temperature.
When the coolant temperature reaches the warning threshold,
the CHECK ENGINE LED on the panel illuminates. If tlie
coolant temperature exceeds the shut-down threshold, the
ECU will·open the K2 and K3 relays shutting down the
generator and the coolant temperature LED on the panel will
illuminate.
High/Low RPM Shutdown
The ECU monitors engine rpm via the MPU )Magnetic Pick-
Up) that is mounted under the flywheel. When the engine
speed falls or rises to a pre-set rpm level, the ECU will shut
down the engine and the fault LED for speed will illuminate.